Effects of concurrent discrimination tasks on gait in healthy subjects

Abstract

The objective of this study was to determine the cost of performing a concurrent discrimination and decision-making task (dual-task cost, DTC) while walking to gait kinematics and dynamic stability. The study included 28 healthy young adults without any motor and/or cognitive disorder. An intra-group repeated measures design was applied. Participants were instructed to walk either under normal conditions or while performing an executive task. The executive tasks involved discriminating the color of the lights of two traffic lights and stopping as rapidly as possible when the traffic lights turned red simultaneously. A kinematic analysis of the gait cycle was performed by 3D photogrammetry. Gait cadence and step variability were measured using the GAITRite® treadmill. The results obtained confirm that the duration of single-support during the two steps of the gait cycle tends to decrease in dual task conditions. An especial impact was observed on step length, which explained the 2% reduction in the velocity of displacement of the center of mass. Variability in step time and length increased with dual tasking. No differences were found among dynamic stability factors. We propose using a DTC differential for subjects with motor and/or cognitive disorders as compared to healthy individuals.